An exhaust gas treatment device, such as a catalytic converter or a particle filter, usually has a tubular housing for ducting exhaust gas, in which at least one exhaust gas treatment element is arranged, which may be, depending the constellation of the exhaust gas treatment device, e.g., a catalytic converter element or a particle filter element. It is clear that a plurality of identical and/or different exhaust gas treatment elements may also be arranged in such an exhaust gas treatment device. Conceivable is, for example, the arrangement of an oxidation-type catalytic converter element upstream of a particle filter element or the arrangement of an oxidation-type catalytic converter element upstream of an SCR catalytic converter element, where SCR denotes selective catalytic reduction. It is likewise conceivable to arrange a particle filter element upstream of an SCR catalytic converter element.
Such exhaust gas treatment elements are subject to a certain wear during the operation, so that it may be necessary during the service life of the exhaust system equipped with them to remove, clean and reinstall the exhaust gas treatment element or to replace it with a new one. To ensure that this maintenance can be carried out in a simpler manner, provisions may be made for the respective exhaust gas treatment element to be arranged in an insert, which is itself arranged replaceably in the housing of the exhaust gas treatment device. For example, the complex mounting of ceramic substrates, which may be used in catalytic converters and particle filters, may be carried out in said insert, which can then be arranged replaceably in the housing in a suitable manner.